Adding define to allow Blink and Chrome to use the unoptimized path of SkOffsetImageFilter without affecting Skia.

BUG=

Review URL: https://codereview.chromium.org/54823007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232555 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/skia/skia_library.gypi b/skia/skia_library.gypi
index effaee4..d8e16f7 100644
--- a/skia/skia_library.gypi
+++ b/skia/skia_library.gypi
@@ -420,6 +420,10 @@
     # SkGraphics::Init().
     'SK_ALLOW_STATIC_GLOBAL_INITIALIZERS=0',
 
+    # Forcing the unoptimized path for the offset image filter in skia until
+    # all filters used in Blink support the optimized path properly
+    'SK_DISABLE_OFFSETIMAGEFILTER_OPTIMIZATION',
+
     # Disable this check because it is too strict for some Chromium-specific
     # subclasses of SkPixelRef. See bug: crbug.com/171776.
     'SK_DISABLE_PIXELREF_LOCKCOUNT_BALANCE_CHECK',